Plug and seal design for adjustable blade propeller turbine

ABSTRACT

In many propeller type turbines the runner blades are supported in a hollow hub and are pivoted about their axes relative to the hub. The operating mechanism is in many instances contained within the hub. Such operating mechanism frequently requires a pivot pin which is supported in a bore in the hub wall. For ease of manufacture and assembly this bore usually extends completely through the wall of the hub, and a plug is required to seal the end of the bore. A simplified design of such a plug is shown herein wherein an O-ring is utilized to seal the bore and a set screw is threaded into a bore partially in the plug and partially in the hub wall and is tack-welded in place.

United States Patent 1191 Poet [ PLUG AND SEAL DESIGN FOR ADJUSTABLEBLADE PROPELLER TURBINE 75] Inventor: Emanuel M. Poet, York, Pa.

[73] Assignee: Allis-Chalmers Corporation,

' Milwaukee, Wis.

22 Filed: Nov.7, 1972 [211 Appl. No.1 304,497

[52] us. (:1 416/168, 416/244, 416/174 [51] Int. vCl. .L F0ld7/00 [58]Field of Search 416/168, 174, 244, 205

[56] References Cited UNITED STATES PATENTS 3,253,661 5/1966 Feroy416/168 3,380,536 4/1968 Pehrssonet 61; 416/174 3,389,920 6/1968 A11666161. 416/174 x FOREIGN PATENTS OR APPLICATIONS 150,529 9/1937 Austria.Q. 416/168 1451 July 2, 1974 21934 I905 Great Britain 4l6/l74 PrimaryExaminerEverette A. Powell. Jr. Attorney Agent, or Firm-John P. Hines1571 ABSTRACT In many propeller type turbines the: runner blades aresupported in a hollow hub and are pivoted about their axes relative tothe hub. The operating mechanism is in many instances contained withinthe hub. Such operating mechanism frequently requires a pivot pin whichis supported inva bore in the hub wall. For ease of manufacture andassembly this bore usually extends completely'through the wall of thehub, and a plug is 1 required to seal the end of the bore. A simplifieddesign of such a plug is shown herein wherein an O-ring is utilized toseal the bore and a set screw is threaded into a bore partially in theplug and partially in the hub wall and is tack-welded in place;

2 Claims, 5 Drawing Figures PLUG AND SEAL DESIGN FOR ADJUSTABLE BLADEPROPELLER TURBINE applicable to a propeller turbine wherein the guidevanes are adjusted by means of a mechanism contained within the turbinehub.

The blades of an adjustable blade turbine frequently referredto in theindustry as a Kaplan turbineare adjustable so as to obtain the optimumefficiency of the turbine under its entire range of operation.Essentially the-turbine runner blades are pivotally supported by ahollowhub from which the blades project uniformally, thehub havingsuitable bearings which pivotally receive trunnions projecting from theblades. The blades can be varied in pitch simultaneously betweenpredetermined optimum open and closed positions within required limitsby the use'of an operating mechanism such as a hydraulic servomotorusually contained within the hollow hub or in the turbine shaft- Thisoperating mechanism is usually in the form of a hydraulic servomotorwhich is connected to a crank arm on the trunnion of the blades by meansof a mechanical linkage. Frequently thismechanical linkage requires apivot pin which is usually supported in a bore which e xtends throughthe outer wall of the turbine hub. After the pin is properly inserteditis necessary to effectively seal the bore so that water passing aroundthe outside of the .hub does not enter the interior thereof and also tokeep the pressurized oilon the inside of the hub from leaking out.

In the past this bore hasbeen effectively sealed by inserting a plug inthe bore and providing a weld between the adjacent surfaces of the plugand the hub. This procedure, although satisfactory, is considerablyexpensive because of the time involved in providing the weld.Furthermore, in the event that repair is required, the weld had to beremoved which also was a time consuming operation. c

It is therefore the general intention and object of this invention toprovide a plug for the pivot pin'bore of ation is read in light of theattacheddrawings wherein:

. FIG. 1 is a side elevation of a typical Kaplanrunner;

FIG. 2 is an enlarged section of the prior art plug and seal; 2

FIG. 3 is an enlarged view of the new design plug and seal; v

FIG. 4 shows a cross-sectional view of a portion of a Kaplan runnerutilizing the subject invention; and

FIG. 5 is a view of the mechanical linkage taken on line V-V of FIG. 4.

hydraulic turbineof the hereinbefore described type which can be moreeasily installed and removed than prior art plugs.

An additional object of the subject invention is to provide a plug for apivot pin bore of a hydraulic turbine of the hereinbefore described typewherein the liquid seal is provided by an annular sealing element heldin a groove provided in either the bore wall or plug surface and theplug is held in place by an engaging member contained in an openingpartially in the plug and partially in the hub wall and tack-welded tothe hub.

A more specific object of the subject invention is to provide a plug ofthe hereinbefore described type wherein an annular groove is provided inthe plug to receive the annular sealing element and a threaded bore isprovided partially in the plug and partially in the hub wall with a setscrew turned therein, and the set screw is tack welded in place.

These and other objects of the subject invention will become more fullyapparent as thefollowing descrip- Referring tothe. drawings a hollowturbine runner hub is generally indicated as 6. The hollow hub 6 has aplurality of circurnferentially spaced blades 7 (herein shown as 4)pivotally connected to the hub. Each blade is provided with a trunnion 8which extends through a sleeve bearing 9 and terminates in the interiorof the hub. The blades extendradially outward from the hub and areactedupon by the water to rotate the runner in-the conventional mannergenerally known in the art.

The operating mechanism for oscillatingthe turbine blades isalsocontained withinv the hub 6. As shown herein forpurposes ofillustration, this. operating mechanism includes a reciprocable shaft 11extending through the hub to a cross-head 12. This cross-head isconnected by a mechanical linkage to the blade trunnion.

- The mechanical linkage includes a link bolt 13 connected' to thecrossrhead l2 and a set of links 10 connecting the link bolt to one arm14 of a bell crank l5. The other arm 16 of the bell crank is in turnconnected to connecting links 17 which areattached to a rockerarm 18connected to the trunnion 8. The bell crank I5 'is pivotally supportedby a pivot pin-l9. One end of this pivot pin is supported in a bore 20extending through the wall of the hub 6. i

I Referring now to FIG. 2, in the prior art design the pivot pin wassealed from the exterior of the hub by means of a plug 21 inserted intheouter end of the bore 20 and held in place by a weld ring 22. Athreaded bore 23 was provided in the plug 21 and a threaded insert 24was thenturned into the threaded bore. This insert was again welded tothe plug as at 26. It can be seen that this design required considerabletime both in application and in the event that removal was necessary.

Now referring to FIG. 3 the new design includes an annular groove 27provided in the outer surface of the plug 28. A ring type sealingelement herein shown as an O-ring 29 is inserted in the annular groove27. It should be understood that this annular groove could be providedin the interior surface of the bore rather than the plug. The plug 28 isthen inserted in the bore and a threaded opening 31 is drilled andtapped. This opening is received partially in the wall of the hub 6 andthe side wall of the plug 28. A set screw 32 is then turned into thethreaded bore 31 adequately holding the plug and hub against bothrotational and axial relative movement. To insure the set screw stays inthe 1. A hydraulic turbine adapted for operation in a liquid mediumhaving walls defining a hollow runner hub, blades having trunnionsmounted for oscillation in said hub, operating means supported withinsaid hub for imparting oscillating movement to said blades, mechanicallinkage means connecting said operating means to said blades including apivot pin supported in a bore extending through said hollow hub wall,and means for sealing said bore from the exterior of said hubcomprising; a plug located in said bore between the terminal end of saidpivot pin and the outer surface of said hub wall; a sealing ringengaging said plug and said bore wall to provide a liquid tight sealtherebetween; walls defining a longitudinally extending opening existingpartially in said hub wall and partially in said plug, the

outer end of said opening being open to the exterior of said hub and theinner end presenting blind end walls terminating short of said sealring; engaging means contained in said opening and engaging both saidhub and said plug to prohibit relative rotation therebetween andengaging said end walls to prohibit relative longitudinal movementtherebetween; and a tack weld between said engaging means and said hubto hold said engaging means and said plug in place.

2. The hydraulic turbine sealing means set forth in claim 1 wherein saidopening is a threaded bore and said engaging means is a set screw whichprevents both relative rotational and longitudinal movement between saidplug and said hub. v

1. A hydraulic turbine adapted for operation in a liquid medium havingwalls defining a hollow runner hub, blades having trunnions mounted foroscillation in said hub, operating means supporTed within said hub forimparting oscillating movement to said blades, mechanical linkage meansconnecting said operating means to said blades including a pivot pinsupported in a bore extending through said hollow hub wall, and meansfor sealing said bore from the exterior of said hub comprising; a pluglocated in said bore between the terminal end of said pivot pin and theouter surface of said hub wall; a sealing ring engaging said plug andsaid bore wall to provide a liquid tight seal therebetween; wallsdefining a longitudinally extending opening existing partially in saidhub wall and partially in said plug, the outer end of said opening beingopen to the exterior of said hub and the inner end presenting blind endwalls terminating short of said seal ring; engaging means contained insaid opening and engaging both said hub and said plug to prohibitrelative rotation therebetween and engaging said end walls to prohibitrelative longitudinal movement therebetween; and a tack weld betweensaid engaging means and said hub to hold said engaging means and saidplug in place.
 2. The hydraulic turbine sealing means set forth in claim1 wherein said opening is a threaded bore and said engaging means is aset screw which prevents both relative rotational and longitudinalmovement between said plug and said hub.